KR20010064622A - Apparatus for contactorless direct current circuit breaking by semiconductor element in electrical power transmission system - Google Patents

Abstract

PURPOSE: A contactless direct current breaker is provided to secure a rapid operation speed, limit an accident current by using a power semiconductor device. CONSTITUTION: The first lighting arrester(32) absorbs an accident current when the accident is inputted to a power(10). A switching part(33) divides the accident current to perform a cutoff function. The switching part(33) consists of a resistor, a semiconductor device, and a flyback diode. The second lighting arrester(34) absorbs an inrush current flowing into the switching part(33). A current transformer(35) senses a magnitude of a conduction current at a back stage of the switching part(33). An over-current sensing part(42) senses an over-current from the conduction current. A current slope sensing part(43) senses a current slope of the conduction current flowing from a cutoff block(30). A gate control part(44) controls a cutoff function of the cutoff block(30) when the accident current is sensed from the sensing parts(42,43).

Description

Contactless DC power circuit breaker using semiconductor device of power converter {Apparatus for contactorless direct current circuit breaking by semiconductor element in electrical power transmission system}

The present invention relates to a non-contact DC power circuit breaker, in particular, by using a semiconductor device for power in the power conversion device, the operation speed is fast, the fault current can be limited, and the semi-permanent lifetime is suitable when performing the DC power blocking function A contactless DC power circuit breaker using a semiconductor device of a power converter.

In general, the circuit breaker is located at the front end of the load side to block the inflow of the over-power when the inflow power exceeds a certain limit to protect the specific circuit of the rear end from the overpower.

These circuit breakers are divided into DC type and AC type according to the power to be cut, and can be classified into gas type, liquid type, and vacuum type according to the type of SOHO, and are manufactured with emphasis on high voltage or high current. And so on.

The conventional mechanical circuit breaker cuts off the accident power by separating the contacts in a high speed operation, and the arc arced between the contacts degrades the circuit breaking performance in a high speed operation that interrupts the accident power. It has a function and structure.

In particular, in the case of a high current breaker, if the circuit voltage is below the minimum calling voltage or the breaking current is not below the minimum holding current, an arc is triggered between the electrodes. Current inflow continues and current blocking is not effective.

Therefore, arc extinguishing method is needed to quickly extinguish arc arced between the contacts. As arc extinguishing method, cooling the arc with the extinguishing medium to lower the temperature, making the circuit voltage below the arc holding voltage, The method of removing the electron or ion which comprises this is mentioned.

In the case of using the extinguishing medium, the extinguishing medium is used in a space in which the fixed contactor and the movable contact flow in the breaker to cool the minimized arc or minimize arcing. Inlet breaker, sulfur hexafluoride, which rapidly cools arcs fired using non-combustible oils as coolant, depending on the SOHO medium. There is a gas circuit breaker that suppresses arc arcing by using an inert gas such as) and a vacuum circuit breaker which prevents arc arcing by realizing high insulation by maintaining the inside of the circuit breaker in a super vacuum state.

However, such a circuit breaker using a conventional arc extinguishing medium is difficult for the breaker to cut off the accident power quickly when the accident power flows into the circuit to be protected, and the mechanical structure for processing the arc arced in the breaker is complicated. As a result, activities such as maintenance / inspection / repair of the circuit breaker are required, which makes it difficult to realize breaker performance and speed.

Accordingly, the present invention has been proposed to solve the conventional problems as described above, an object of the present invention is to use a semiconductor device for power in the power conversion device, the operation speed is high when the DC power blocking function is performed, limiting the fault current It is possible to provide a non-contact DC power circuit breaker using a semiconductor device of a power converter suitable for having a semi-permanent life.

In order to achieve the above object, a non-contact DC power circuit breaker using a semiconductor device of the power converter according to the present invention, the blocking block for performing a function to block the fault current and detect the energized current; The technical configuration is characterized by consisting of a control block for controlling the fault current blocking function of the blocking block by using the energizing current detected by the blocking block.

1 is a block diagram of a contactless DC power circuit breaker using a semiconductor device of a power conversion apparatus according to an embodiment of the present invention,

FIG. 2 is a detailed block diagram of one phase in FIG. 1.

3 is an operational waveform diagram of the apparatus shown in FIG.

Explanation of symbols on the main parts of the drawings

10: DC power supply side 20: load side

30: blocking block 32: first lightning protection

33: switching section 34: second lightning protection

35 current converter 40 control block

42: overcurrent detection unit 43: current slope detection unit

44: gate control unit

Hereinafter, the configuration and operation according to an embodiment according to the technical concept of the contactless DC power circuit breaker using the semiconductor device of the power conversion device of the present invention as described above will be described in detail.

First, Figure 1 is a block diagram of a contactless DC power circuit breaker using a semiconductor device of the power conversion apparatus according to an embodiment of the present invention, Figure 2 is a detailed block diagram of the phase 1 in Figure 1, Figure 3 is This is a waveform diagram of the device.

As shown in FIG. 1, the breaker according to the present invention includes a blocking block 30 that performs a function of blocking an accident current and detects an energized current; It is composed of a control block 40 for controlling the fault current blocking function of the blocking block 30 by using the energized current detected by the blocking block 30.

The blocking block 30 may include: a first lightning arrester 32 for absorbing an accident current between a phase and a ground when an accident current is input at the power supply side 10; A switching unit 33 for dividing the fault current to perform a blocking function; A second lightning arrester 34 for absorbing the load-side inrush current flowing into the switching unit 33 between the phase and the ground; The current transformer (Current Transformer) 35 for sensing and outputting the magnitude of the conduction current at the rear end of the switching unit 33.

The control block 40, the over-current detecting unit 42 for detecting an over-current in the energized current input from the blocking block 30; A current slope detector 43 for detecting a current slope of an energized current input from the blocking block 30; When the fault current is sensed by the overcurrent detector 42 and the current slope detector 43, the gate controller 44 controls the blocking function of the blocking block 30.

As shown in Fig. 2, the switching section 33 includes: a voltage dividing resistor 51 for dividing the voltage input from the power supply side and outputting the divided voltage to the semiconductor element 52; A semiconductor device 52 which conducts electricity when the current divided and input by the voltage dividing resistor 51 is a normal current and cuts off an accident current; Snubber parts 53 to 55 absorbing the fault current when the fault current is input into the semiconductor device 52; The semiconductor device 52 includes a flyback diode 56 that circulates current accumulated in an inertial device when the fault current is blocked.

Referring to the operation of the device according to such a configuration as follows.

By installing a circuit breaker according to the present invention at the front end of the load side 20 into which the DC power is drawn from the DC power supply side 10 along the transmission line, the circuit breaker according to the present invention operates normally to supply the operating current to the load side 20. In the state in which the accident power is introduced, the accident power is blocked by a solid state to prevent the accident power from flowing into the load side 20.

First, when an accident power is input from the DC power supply side 10 to the load side 20 along the transmission line, when the input current is within the range of the normal current in the blocking block 30, the load side 20 is energized. When the input current is an accident current exceeding the limit range of the normal current, a switching operation is performed to block the accident current from being energized to the load side 20.

When the fault current is input from the DC power supply side 10, a switching operation is performed in which the fault current is blocked by the power semiconductor element in the switching unit 33 after being detected by the potential converter 31.

In the switching unit 33, as shown in FIG. 3, the input power is divided by the voltage dividing resistor 51 and output to each semiconductor element 52 connected in series.

At this time, the semiconductor device 52 is a power semiconductor device such as IGBT, IGCT, thyristor, GTO, or transistor, and energizes during normal current input and cuts off the fault current by performing switching operation when the fault current is input. Done.

When the fault current is blocked in the semiconductor device 52, snubber parts 53, 54, and 55 absorb the blocked fault current by a resistance-capacitor parallel circuit.

In addition, the flyback diode 56 emits electrical energy accumulated in each inertial element of the load side 20 or the switching unit 33 to the DC power supply side 10 by blocking the fault current in the semiconductor device 52.

According to the present invention, a unit block including the voltage divider 51, the semiconductor element 52, the snubber portions 53, 54, 55, and the flyback diode 56, which operate as described above, is a single unit. The circuit breakers suitable for various operating environments can be realized by connecting a plurality of circuits.

That is, a high power circuit breaker can be implemented by connecting a plurality of unit blocks in series, and a high current circuit breaker can be implemented by connecting a plurality of unit blocks in parallel. For example, by connecting the above four unit blocks in series and in parallel it is possible to implement a 3.6kV circuit breaker. Therefore, the 4000A / 4500V power semiconductor device can be configured in series and parallel to be applied to the 3.6kV ~ 25.8kV class DC circuit breaker system.

When the fault current is interrupted by the switching unit 33, the fault current is absorbed between the phase and the earth in the first lightning arrester 32 without being input to the load side 20.

In addition, when a rush current occurs due to a short circuit accident on the load side 20 and flows back to the DC power supply side 10, the second lightning arrester 34 absorbs the rush current between the phase and the ground.

When the switching unit 33 performs the function of blocking the fault current, the fault current flows into the load side 20 during an operation time until the fault current is detected and the blocking operation of the fault current is completed. .

The fault current flowing into the load side 20 during the operation time is detected by the current converter 35 and output to the overcurrent detector 42 and the current slope detector 43 of the control block 40.

When performing the function of blocking the fault current in the blocking block 30, the control block 40 controls the blocking block 30 to limit the fault current to a certain amount of current to suppress the flow of excessive current, The limited current is quickly removed at near natural zero.

That is, the overcurrent detector 42 and the current slope detector 43 receive the detection signals of the current converter 35, respectively, to determine whether excessive current flows in and whether the slope of the current flow exceeds a specific range. By sensing each, accident current is detected. That is, the overcurrent detector 42 and the current slope detector 43 monitor the energized current to detect the energized current exhibiting the characteristic as an accidental current, and output it to the gate controller 44.

When the fault current is sensed by the overcurrent detector 42 and the current slope detector 43, the gate controller 44 controls the switching unit 33.

The control signal of the gate controller 44 detects when the fault current input to the switching unit 33 does not exceed a predetermined size and performs a blocking operation, thereby limiting the fault current to a state close to the natural zero.

By blocking the limited fault current as described above, the operation time from the fault current detection until the fault current is blocked is shortened. For example, the operation time of a conventional mechanical circuit breaker is several milliseconds (msec), but the operation time of the circuit breaker according to the present invention is several microseconds (usec) to achieve high speed. That is, the breaker according to the present invention can be speeded up by the operating characteristics of the semiconductor element used in the switching unit 33, the operation time is very short.

The operating waveform of the DC power circuit breaker according to the present invention monitors the energizing current as shown in FIG. 3 and when the current slope exceeds a certain range or the current magnitude is more than a predetermined value (detection level, detector level), an accident current Will be blocked. At this time, since the speed can be increased by the operation characteristics of the power semiconductor element used in the switching unit 33, the operation time is very short.

As described above, the present invention uses a semiconductor device for power to quickly open a fault current of direct current to a contactless state, so that there is no arcing and stable blocking operation is performed in a state where the electric energy accumulated in the load side circuit is minimal.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments. Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

As described above, the contactless DC power circuit breaker using the semiconductor device of the power converter according to the present invention is a high-speed cut-off, arc-free, non-interruption that is difficult to realize the conventional mechanical contact breaker by using the power semiconductor device as a switching device There is an effect of realizing ideal breaker characteristics such as maintenance.

In addition, since a phenomenon such as mechanical wear due to contact opening and closing of a conventional circuit breaker does not occur, it may be easily applied where a high frequency high speed opening and closing is necessary, and applied to a place requiring a function of a soft starter for inrush current control. It can be effective.

In addition, since it is easier to control the fault current as compared to the conventional circuit breaker, there is an effect of reducing the cost according to the system configuration by simplifying the equipment such as the input terminal power equipment and the peripheral cable capacity.

Claims (5)

A blocking block which performs a function of blocking an accident current and detects an energized current; A contactless DC power circuit breaker using a semiconductor device of the power converter, characterized in that the control block for controlling the fault current blocking function of the blocking block by using the energizing current detected by the blocking block. The method of claim 1, wherein the blocking block, A first lightning arrester for absorbing the fault current between the phase and the ground when the fault current is input from the power supply side; A switching unit performing a blocking function by dividing the accident power; A second lightning arrester configured to absorb a load-side inrush current flowing into the switching unit between a phase and a ground; A contactless DC power circuit breaker using a semiconductor device of the power converter, characterized in that the current converter for sensing and outputting the magnitude of the conduction current at the rear end of the switching unit. The method of claim 1, wherein the control block, An overcurrent detector for detecting an overcurrent from an energized current input from the blocking block; A current slope detector configured to detect a current slope of an energized current input from the blocking block; The contactless DC power circuit breaker using the semiconductor device of the power converter, characterized in that the gate control unit for controlling the blocking function of the blocking block, when the accident current is detected by the overcurrent detection unit or the current slope detection unit. The method of claim 2, wherein the switching unit, A voltage divider resistor for dividing the voltage input from the power supply side and outputting the divided voltage to the semiconductor element; A semiconductor device configured to conduct electricity when the current divided and input by the voltage dividing resistor is a normal current and cut off when a fault current is generated; A snubber unit for absorbing the fault current when the fault current is input into the semiconductor device; A non-contact DC power circuit breaker using a semiconductor device of the power conversion device, characterized in that the semiconductor device of the power converter is configured to circulate the current accumulated in the inertial device when the fault current is blocked. The method of claim 2, A contactless DC power circuit breaker using a semiconductor device of the power converter, characterized in that for connecting the switching unit in series or in parallel to configure a high power circuit breaker.